Cutter head assembly

ABSTRACT

A cutter head assembly adaptable for use on a plotter-type mask making apparatus utilizes a plurality of actuators within a block each operable by a controllable solenoid. Each actuator includes a guide and a relatively movable plunger thereon which is vertically aligned with a cutting or scribing instrument which is retained by an insert guide member fixed within a plate below the actuator. Both the stroke of the cutting instrument and its pressure on material being cut are controllable by adjustments on the actuator.

United States Patent [5 6] References Cited UNITED STATES PATENTS [721 inventor Gerald S. Domagalski San Jose, Calif.

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Santa Clara, Calif, Primary Examiner- Harry N. Haroian Attorney-Owen, Wickersham and Erickson ABSTRACT: A cutter head assembly adaptable for use on a plotter-type mask making apparatus utilizes a plurality of actuators within a block each operable by a controllable solenod. Each actuator includes a guide and a relatively movable plunger thereon which is vertically aligned with a cutting or scribing instrument which is retained by an insert guide member fixed within a plate below the actuator. Both the stroke of the cutting instrument and its pressure on material being cut are controllable by adjustments on the actuator` 80 :9 umn, uomn M/O 433 B36, 2 u B. Mm m m m m Am D m m w mn m.h D WN H6 mma ms, m. I mc/ Mmm t C5 Umm H MUM D www 4 l Avi FFind-Haig" am t PAENEU JULQOIQY:

SHEET l UF 2 FIG 5 FlG 6 INVENTOR.

GERALD S DOMAGALSKI ATTORNFYS PMENIEnJuLeom 35933126 SHEEI 2 UF 2 ffl@ F l G 4 A I INVENTOR.

GERALD '5. DOMAGALSKI lATTORNEYS CUTTER HEAD ASSEMBLY This invention relates to an improved scribing or cutting head adaptable for use on a plotting-type cutting and drawing machine.

Such machines are used extensively in the automated drawing and cutting of intricate patterns such as required for integrated circuit masks. Generally such a machine operates like a plotter with a movable head that is drawn in a predetermined programmed two-dimensional path. The mask is a sheet of plastic material of a unifonn thickness (e.g. 7 mils) which has an upper layer of gel (e.g. 2 mils). To prepare the enlarged photo mask of a complicated semiconductor circuit pattern, the gel layer must be cut along appropriate border lines by an instrument that penetrates to a depth slightly greater than the gel. After the sheet has been cut in accordance with a predetermined mask pattern, portions of the gel layer are peeled off to form the photo negative of the circuit mask. In apparatus heretofore provided to accomplish such mask making, a cutting instrument was provided in a movable head which was operated by the automated plotting mechanism. However, problems arose in providing a cutter head capable of maintaining the proper alignment of the cutting instrument when it moves to the cutting position. Any appreciable deflection of the cutting instrument causes the cutting lines to vary outside of the close tolerances required in mask making.

One object of the present invention is to solve the aforesaid problem by providing a cutter head assembly that will maintain a cutting or scribing instrument in proper alignment with negligible deflection when the instrument is in a cutting posi tion.v 2

Another object of the presentl invention is to provide a cutter head assembly for a plotting-type mask maker wherein the stroke of the cutting instrument can be changed easily anclA with precisionto accommodate different thicknesses of mask material.

Yet another object of the present invention is to provide a cutterassembly that s easier to maintain and service.

ln, accordance with the principles ofthe invention, my cuttenheadassembly comprises a main block within which are mounted a plurality of linearly movable actuators. Each actuator is aligned with a cutting instrument retained by an insert in a guide plate located below the block. A solenoid is connected to eachfactuator to provide a downward movement which causes it toengage the aligned cutting instrument and push it into the cutting position. The actuator is positioned to move against a first spring, and the cutting instrument is movable against a second spring that affords retraction of the instrument when the actuator returns to its neutral position. The cutting instrument is slideably supported within a cylindrical bore of considerable length so that it cannot wiggle or deflect when in the cutting position. Since the actuator with its solenoid is separate from the cutting instrument the latter is relatively easy to change when worn or when it must be repositioned to accommodate achange in `direction for the movable cutter head.

Other objects, advantages and features of the invention will become apparent from the following` detailed description l v thereof presented in conjunction with the accompanying drawings, in which:

FIG. l is a somewhat schematic view in perspective showing a typical automated mask-making apparatus adapted to utilize a cutter head lembodying the principles of the present invention;

FIG. 2 is an. enlarged front view in elevation and in section of the cutter head shown in FIG. l;

FIG. 3 vis an enlarged, fragmentary side view in elevation and in section of the cutter headk shown in FIG. 2;

FIG 4 is an enlarged fragmentary bottom view of the cutter head of FIGS; 2 and 3;

FIG.r 5 is a fragmentary front view in elevation of a modified form of cutter head according to my invention; and

FIG. 6 is a fragmentary side view in elevation of the i mated production of semiconductor masks, comprises.

generally a plotting board or platen 14 to which a sheet 16 of mask material such as sheet plastic with an upper gel layer is secured. Along opposite sides of the board are a pair of parallel rails 18 which support the opposite ends of a movable crossbeam 20. The beam is perpendicular to and supported by the rails so that it can be moved to any predetermined position along them. Mounted on the beam for linear movement alongside it is the cutter head l0. It is to be understood that the cutter or scriber machine shown is merely representative of a typical apparatus on which my cutter head may be mounted and the present invention is not limited by any particular twodimensional plotting-type apparatus or mask-making machine.

As shown in an enlarged view in FIG. 2, one form of my cutter head l0 comprises generally a main body or block 22 in which a plurality of vertically movable actuators 24 are mounted. Each of these actuators controls a knife or scriber instrument 26 and the blades 28 of these instruments can be oriented in different positions to accommodate the different linear directions of travel of the head assembly l0 over the platen 14.V When the cutter assembly moves, the actuator controlling the knife whose blade is aligned with the direction of movement is energized to make the appropriate cut. To simplify the explanation of the invention, only one actuator with its associated knife is shown in detail since all other actuators would be identical in construction and function.

Each actuator 24 comprised a generally tubular guide member 30 having a central passage 32 of constant diameter, the guide member itself being located within a bore hole 34 in the actuator block 22. Near its upper end the guide member has an integral ring portion 36 forming an annular shoulder 38 that serves to help retain an armature 40 of a solenoid. The armature has an annular shape and may be secured to the guide member by a-suitable bonding adhesive. A coil 42 for the solenoid is secured within the block and is located around the armature so as to cause it to react magnetically when the coil is supplied with electrical current. Lead wires to the coil are not shown since they may be connected in any suitable, wellknown manner. Above the solenoid armature is a threaded neck portion 44 of the guide member 30'to which is attached a barrellike tubular cap 46 having an internal cylindrical chamber 48.

Within the guide member is a plunger 50 which is generally cylindrical and has upper andlower enlarged sections 52 that slidably fit within its central passage 30. At the upper end of the plunger is an enlarged head portion 54 that is normally retained against an internal annular shoulder 56 within the lower end of the chamber 48 of the cap 46. A coil spring 58 within the cap chamber bears against the enlarged plunger head portion 54 and is held in place by an adjustable setscrcw 60 threadedly engaged in the upper end of the cap chamber 48.

The integral ring portion 36 of the guide member 30 engagesfa movable collar 62 that forms a seat for the upper end of an actuator return spring 64. The lower end of this spring is seated on a plate 66 having an opening 68 that surrounds the guide member with ample clearance.

As shown in FIG. 3 the block 22 has an overhanging portion along one side within which the actuators 24 are located. Spaced below` the overhanging portion is a guide plate 70 within which the cutting instruments 26 for the actuators are mounted. Each cutting instrument has a main cylindrical portion 72 above its blade portion 28 that is slidable within a central passage 74 of a cylindrical guide insert 76. There is a guide insert'76 and thus a cutting instrument 26 for each actuator 24 and the insert is located in the guide plate 70 so that the upperv cylindrical end of the cutting instrumentA is directly below the plunger 50 ofthe actuator, Each guide insert, as shown in FlG. 4, fits into a recess 78 extending upwardly from the bottom of the guide plate, and it has a locator pin 80 extending radially from one side thereof. The latter tits in a slot 82 in the bottom of the guide plate and thereby orients the blade 28 of the cutting instrument 26 in a predetermined direction relative to the guide plate. A setscrew 84 extending inwardly from the side of the guide plate holds the guide insert in place within the guide plate.

An upper end portion 86 of the guide insert has insert has a smaller diameter than its base and is provided with a diametral slot 88 which is open at the upper end of the insert. A pin 90 tits within the slot and also extends transversely through the upper end of the cylindrical portion 72 of the cutting instrument, thereby maintaining its fixed position and preventing any rotation within the insert. Underneath the pin is a cup washer 92 that retains the upper end of a coil spring v94 located around the upper portion of the guide insert 76. The lower end of the spring 94 is seated within an annular recess 96 formed in the lower portion of the guide insert.

ln operation, the lower end 98 of the actuator plunger 50 normally rests on the upper end of the cutter instrument, When current is supplied to the solenoid coil of an actuator, the actuator guide member 24 in the block 22 moves downwardly. until it engages the upper end 100 of the guide insert. Depending on how much tension is preset in the spring 58 within the actuator barrel cap 46, the plunger 50 will cause the cutting instrument 26 to move downwardly below the guide plate 70 a predetermined amount. The cutting instrument will hold this extended cutting position until the solenoid is deactivated and its return spring 64 moves the guide member 24 upwardly to its neutral position. This moves the major force on the upper end of the cutting instrument, and the return spring 94 thus forces it to the retracted position.

The amount or length of stroke is seen to be adjustable by turning the barrel cap 46 on the actuator guide 24, which changes the relative axial positions of the actuator guide and the plunger. For example in FIG. 2, if the barrel cap is threaded downwardly, it internal spring is still sufficient to keep the plunger head 54 against the shoulder 56 and thus the stroke length, that is, the distance between the end of the actuator guide and the top ofthe insert guide 76 is increased.

The internal spring 58 within the barrel cap has no effect on stroke length but it does control the amount of pressure of the cutter knife. B y turning the setscrew 60 to decrease the length of the chamber in the barrel cap, this spring 58 is compressed and thereby controls the force exerted by the plunger on the cutter instrument when the actuator guide is against the guide insert. As the actuator starts down, the movement of the cutter instrument and thus the plunger is opposed by the cutter return spring. However, when the actuator has moved some nite distance, the opposing force of the cutter spring is overcome and the cutter moves downwardly to its adjusted cutting position.

ln the arrangement of the present invention, as shown in FIGS. 2 4, the cutting instrument 26 is fully supported within the cylindrical passage of the insert guide 76, and any possibility of side movement or deflection thereof is eliminated. Somewhat less but still sufficient support under most circumstances for the cutting instrument is afforded by the structural arrangement of FIG. wherein a return spring 94a is located on the inside of an insert guide member 76a. Here the insert member has an upper portion 86a with a larger diameter that provides an annular recess 102 for accommodating a return spring 94a which is seated at the bottom of the recess at its lower end and against the washer 104 retained by a cross pin a at its upper end. Since a substantial amount of length of the cutting instrument is constantly within a cylindrical passage of the insert guide in this modified version, no appreciable side deflection of the cutting blade can occur and the cutter head can be operated with a high degree of preci'-, y.

sion.

To those skilled in the art to which this invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the spirit and scope of the invention. The disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.

lclaim:

l. A cutter head assembly adapted to be moved linearly on a platen for cutting or scribing planar surfaces on sheet material, s-aid assembly comprising:

a block having a vertical bore;

an actuator in said bore including;

a movable guide member having a central passage and a plunger .having an enlarged head and axially movable in said passage relative to said guide member;

adjustable means connected to the upper end of said guide member for exerting; a predetermined, continuous but yieldable axial force on said plunger;

means on said guide member for actuating it axially from a neutral position downwardly into a cutting position, and means for moving said guide member back upwardly into the neutral position;

a guide plate spaced below said block;

a guide insert mounted in a fixed position in said guide plate and having a portion forming a guide bore;

an elongated cutting instrument in said guide bore having a cutting tip at its lower end and a main body portion with a blunt upper end axially aligned with and engaged by the lower end of said plunger;

and means retained by said guide insert for retracting said cutting instrument when said guide member moves to its neutral position.

2. The cutter head assembly as described in claim l wherein said adjustable means comprises a hollow, tubular cap having an internal shoulder for limiting the downward travel of said plunger head therein and coil spring means within said cap having one end bearing against said plunger head and tending to hold it against said shoulder, and a setscrew threadedly engaged in said cap and bearing against the other end of said coil spring.

3. The cutter head assembly as described in claim l wherein said guide bore forms a close sliding flt with said main body of said cutting instrument near the lowerend thereof.

4. The cutter head assembly as described in claim l wherein said guide insert comprises a lower cylindrical portion retained within said guide plate and having said bore, and an upper tubular portion, said means for retracting said cutting instrument comprising a coil spring extending around said upper portion.

5. The cutter head assembly as described in claim 1 wherein said guide insert comprises a lower cylindrical portion retained within said guide plate and having said bore, and an upper tubular portion, said means for retracting said cutting instrument comprising a coil lspring extending around said cutter instrument and located within said upper insert portion. 

1. A cutter head assembly adapted to be moved linearly on a platen for cutting or scribing planar surfaces on sheet material, said assembly comprising: a block having a vertical bore; an actuator in said bore including; a movable guide member having a central passage and a plunger having an enlarged head and axially movable in said passage relative to said guide member; adjustable means connected to the upper end of said guide member for exerting; a predetermined, continuous but yieldable axial force on said plunger; means on said guide member for actuating it axially from a neutral position downwardly into a cutting position, and means for moving said guide member back upwardly into the neutral position; a guide plate spaced below said block; a guide insert mounted in a fixed position in said guide plate and having a portion forming a guide bore; an elongated cutting instrument in said guide bore having a cutting tip at its lower end and a main body portion with a blunt upper end axially aligned with and engaged by the lower end of said plunger; and means retained by said guide insert for retracting said cutting instrument when said guide member moves to its neutral position.
 2. The cutter head assembly as described in claim 1 wherein said adjustable means comprises a hollow, tubular cap having an internal shoulder for limiting the downward travel of said plunger head therein and coil spring means within said cap having one end bearing against said plunger head and tending to hold it against said shoulder, and a setscrew threadedly engaged in said cap and bearing against the other end of said coil spring.
 3. The cutter head assembly as described in claim 1 wherein said guide bore forms a close sliding fit with said main body of said cutting instrument near the lower end thereof.
 4. The cutter head assembly as described in claim 1 wherein said guide insert comprises a lower cylindrical portion retained within said guide plate and having said bore, and an upper tubular portion, said means for retracting said cutting instrument comprising a coil spring extending around said upper portion.
 5. The cutter head assembly as described in claim 1 wherein said guide insert comprises a lower cylindrical portion retained within said guide plate and having said bore, and an upper tubular portion, said means for retracting said cutting instrument comprising a coil spring extending around said cutter instrument and located within said upper insert portion. 